Preparation of phosphorus sulfidehydrocarbon reaction products



United States Patent PREPARATION OF PHOSPHORUS SULFIDE- HYDROCARBON REACTION PRODUCTS Norman E. Lemmon, Hammond, Ind., Edward N. Roberts, Los Altos, Calif., and Albert R. Sabol, Munster, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application May 31, 1956 Serial No. 588,262

9 Claims. (Cl. 260-139) This invention is directed to improvements in the preparation of neutralized reaction products of a phosphorus sulfide and a normally liquid hydrocarbon, and more particularly is directed to the preparation of such a reaction product for use as a lubricant additive which has a low viscosity, low trace metals content and is substantially free of salts of inorganic acids of phosphorus and low molecular Weight organic acids of phosphorus.

It has heretofore been found that certain reaction products of a phosphorus sulfide and a hydrocarbon, particularly an olefin or an olefin polymer, when added in small amounts to a hydrocarbon oil, such as a mineral oil, are effective in inhibiting the formation of sludge and/ or varnish-like deposits on the valves, piston rings, etc. of internal combustion engines in which they are employed. While lubricant additives of this type have proven very satisfactory for use under most conditions, it has been observed in some cases that when used in internal combustion engines operating under unusually high temperature conditions and/or used in internal combustion engines, particularly diesel engines, employing motor fuels of high sulfur content, undesirable wear and engine deposits have been encountered. While these difliculties appear to be the exception rather than the rule, steps were taken to overcome such difiiculties. It was found that a contributory factor was the presence of relatively large amounts of salts of inorganic phosphorus acids and low molecular weight organic phosphorus acids formed in the hydrolysis of the reaction products of the phosphorus sulfide and the hydrocarbon. It has been proposed to remove the inorganic phosphorus acids from the hydrolyzed reaction product by contacting with an adsorbent material such as fullers earth. While this has generally proven very efiective, it has recently been observed that trace quantities of various metals are introduced by the adsorbent material. Although this in no way affects the ability of the product to carry out its function. as an additive, it does in some cases interfere with certain analytical procedures used to evaluate the performance of the lubricant and the rate of wear in the internal combustion engine. Moreover, it has been observed that under some conditions, and particularly when striving to obtain a high metal to phosphorus ratio in the final product, the mixture becomes cloudy, viscosity becomes quite high and the product is extremely diflicult to filter. Furthermore, due to the presence of some inorganic phosphorus acids and undesirable organic phosphorus acids, a considerable amount of the basic neutralizing agent employed in preparing a finished additive is consumed neutralizing these undesirable constituents. This, of course, increases the cost of manufacture of the finished additive.

It is an object of the present invention to provide a method of preparing improved neutralized reaction products of a phosphorus sulfide and a hydrocarbon. Another object is to provide a method of removing inorganic and low molecular weight organic acids of phosphorus from the hydrolyzed reaction product of a hydrocarbon 2,843,5Y9 Patented July 15, 1958 and a phosphorus sulfide. Another object of the invention is to provide a method of preparing neutralized re action products of a phosphorus sulfide and a hydrocarbon substantially free of salts of inorganic phosphorus acids and low molecular Weight organic phosphorus acids and having a low trace metals content. Still another object of the invention is to provide a reaction product of a phosphorus sulfide and a hydrocarbon which when neutralized with a basic reagent will be bright, have a low viscosity and be readily filterable.

In accordance with the present invention, neutralized reaction products of a phosphorus sulfide and a normally liquid hydrocarbon, substantially free of salts of inorganic phosphorus acids, salts of low molecular weight organic phosphorus acids and trace quantities of various metals are prepared by reacting such hydrocarbons, particularly olefin polymers, with a phosphorus sulfide, particularly phosphorus pentasulfide, hydrolyzing the resultant reaction product at a temperature of from about 220 F. to about 500 F., preferably from about 300 F. to about 400 F., contacting the hydrolyzed reaction product at a temperature of from about F. to about 212 F., and preferably from about F. to about 200 F., with from about 10% to about 200% by volume, and preferably from about 20% to about 100% by volume of a mixture consisting of water and from about 5% to about 95% by volume of phenol or an alkyl alcohol having from about 1 to about 5 carbon atoms. Examples of suitable alcohols are methanol, ethanol, isopropanol, isoamyl alcohol and the like. The contacting time is not critical and can be varied over a wide range; usually a contacting time of from about one-fourth of an hour to about 20 hours, and preferably from about one-half hour to about 6 hours is sufficient to obtain the desired result. Following this extraction step the alcoholor phenol-water mixture is allowed to separateand is withdrawn.

The phosphorus sulfide-hydrocarbon reaction product can then be neutralized with a basic reagent, such as a basic alkali-metal compound or a basic alkaline earthmetal compound, such as, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide, calcium oxide, magnesium oxide or magnesium hydroxide, or heavy metal hydroxides such as zinc hydroxide, tin hydroxide, or basic nitrogen compounds, such as ammonia, amines, or quaternary alkyl monohydroxides.

In the preparation of the phosphorus sulfide-hydrocarbon reaction product, the hydrocarbon is reacted with a phosphorus sulfide, such as P 8 P 8 P 8 or other phosphorus sulfides, and preferably phosphorus pentasulfide, P 8

The hydrocarbon constituent of this reaction is preferably a mono-olefin hydrocarbon polymer having a molecular weight of from about to about 50,000 and resulting from the polymerization of low molecular weight mono-olefinic hydrocarbons or iso-mono-olefinic hydrocarbons, such as propylenes, butylenes and amylenes, or the copolymers obtained by the polymerization of hydrocarbon mixtures containing iso-mono-oleiins and mono-olefins of less than 6 carbon atoms. The polymers may be obtained by the polymerization of these olefins or mixtures of olefins in the presence of a catalyst such as sulfuric acid, boron fluoride, aluminum chloride or other similar halide catalysts of the Friedel-Crafts type.

Other preferred olefins suitable for the preparation of the hereindescribed phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 carbon atoms to about 18 carbon atoms, and preferably at least 15 carbon atoms are in a long chain. Such olefins can be obtained by the dehydrogenati'on of paraflins, such as by the cracking of paraffin waxes or by the dehalogenation of alkyl halides, prefcrably long chain alkyl halides, particularly halogenated paraffin waxes.

Essentially paraffinic hydrocarbons such as bright stock residuums, lubricating oil distillatcs, petrolatums, or paraffin waxes, may be used. There can also be employed the condensation products of any of the foregoing hydrocarbons, usually through first halogenating the hydrocarbons, with aromatic hydrocarbons in the presence of anhydrous inorganic halides, such as aluminum chloride, zinc chloride, boron fluoride, and the like.

Also contemplated within the scope of the present invention are the reaction products of a phosphorus sulfide with an aromatic hydrocarbon such as, for example, benzene, naphthalene, toluene, xylene, diphenyl and the like or with an alkylated aromatic hydrocarbon, such as, for example, benzene having an alkyl substituent having at least four carbon atoms, and preferably at least eight carbon atoms, such as a long chain paralfin wax.

In general, the preparation of the phosphorus sulfidehydrocarbon reaction product in accordance with the present invention is carried out in the following manner:

The hydrocarbon such as, for example, an olefinic polymer of the desired molecular weight, is reacted with from about 1% to about 50%, and preferably from about to about 25%, of a phosphorus sulfide, e. g., P 8 at a temperature of from about 200 F. to about 600 F. in a non-oxidizing atmosphere, such as, for example, an atmosphere of nitrogen. The reaction is carried out for from about one to about ten hours or more, and preferably for about five hours. The phosphorus sulfidehydrocarbon reaction can, if desired, be carried out in the presence of a sulfurizing agent such as sulfur, sulfur chlorides, etc. The reaction product obtained is then hydrolyzed at a temperature of from about 200 F. to about 500 F., and preferably at a temperature of 300 F. to 400 F., by a suitable mews, such as, for example, by introducing steam through the reaction mass.

The hydrolyzed product containing inorganic phcm phorus acids and low molecular weight organic phosphorus acids formed in the preceding steps is then contacted with a mixture consisting of water and a monohydroxy-compound such as phenol or an alcohol having from one to about five carbon atoms. This extraction step is carried out at a temperature of from about 100 F. to about 212 F., and preferably from about 130 F. to about 200 F. At temperature lower than this, the time to complete the extraction step is uneconomical and at temperatures higher than above indicated the water and/or mono-hydroxy-compound vaporizes too rapidly, thus resulting in high pressures or large and expensive condensers. It is preferable to employ from about 20% to about 100% by volume of the mono-hydroxy-compound water mixture, although from about to about 200% or more by volume may be employed. The monohydroxy-compound water mixture may contain from about 5 to about 95% by volume of the mono-hydroxy compound, and preferably from about to about 60% by volume. It is essential, of course, that the monohydroxy-compound have a water solubility of at least about 5% by volume at reaction temperature.

It is preferable, before contacting the reaction product with the Il'lOl'lOhYdl'O-XY-rCGI'l'lPOUHd water mixture, to dilute the phosphorus sulfide-hydrocarbon reaction product with a normally liquid hydrocarbon, generally the same as, or similar to, the hydrocarbon oil in which the finished additive is to be employed, to a phosphorus content of from about 0.5% to about 5% and preferably from about 1.5% to about 2.5%. The neutralization step is carried out with a suitable basic compound such as a hydroxide, carbonate, oxide or sulfide of an alkaline earth metal or an alkali metal as pointed out 'hereinbefore. It is preferable, however, to use an alkaline earth metal compound and particularly barium oxide. The neutralization is carried out at a temperature of from about 100 F. to about 500 F. and preferably from about 200 F. to about 350 F., using stoichiometric amounts or more of the basic reagents. The neutralization may also be carried 5 out in the presence of an alcohol as described in Serial No. 537,579, filed September 29, 1955, now U. S. 2,806,022, issued September 10, 1957, or in Serial No. 540,168, filed October 12, 1955.

The following examples are illustrative of the hereindescribed invention and are not intended as being indicative of the scope thereof:

EXAMPLE 1 A butylene polymer having a molecular weight of about 400 F. and the reaction product diluted with an equal volume of an SAE5 base oil. The diluted product was then hydrolyzed with steam at a temperature of about 400 F. until the acidity of the product remained substantially constant with continued steaming. The diluted, hydrolyzed product had an acidity of 38 mg. KOH per gram of product and a total phosphorus content of 2.04% by weight, of which 11.4% was in the form of phosphate (P0 The hydrolyzed product was then contacted with various amounts of isopropyl alcohol at various concentrations for a period of one hour, with agitation, at a temperature of from 150 F. to 160 F. The reduction in acidity, total phosphorus content and phosphate content are shown in the following table:

As may be seen by inspection of Table I, the reduction in acidity and phosphorus content is due primarily to the removal of inorganic phosphorus acids. Other phosphorus compounds were also removed, however, and it has been observed that these are relatively low molecular weight organic phosphorus compounds. Larger volumes of watcr-isopropanol can be used to extract the hydrolyzed product. It has been observed in this connection, however, that little benefit is derived from increasing the volume while the costs increasesubstantially.

EXAMPLE 2 The oil-diluted hydrolyzed reaction product of P 8 and butylene polymer of Example 1 was contacted with y various amounts of mixtures of isoamyl alcohol and water for a period of one hour at a temperature between 180 F.

and 200 F. The reduction in acidity, total phosphorus content and phosphate content are shown in the following table:

0 Table II Water-Iso- Isoamyl Ale. Acidity (Mg. Total P, Percent of P amyl Ala, Cone, Vol.- KOH/gm.) percent as -PO| VOL-percent percent 5 20 so so. 2 1.82 2. 2 40 27. 0 1. 80 1. 9 13 75 34.1 1. 95 3.8 27 75 30. 3 1.85 2. 4

The results in this instance are essentially the same as those obtained using the water-isopropanol' mixture.

EXAMPLE 3 The oil-diluted hydrolyzed reaction product of P 5 and butylene polymer of Example 1 was contacted with 50% of aqueous ethyl alcohol (95% ethanol plus 5% 700 was reacted with 15% P 8 at a temperatureof about mer reaction product was reduced about 50%. The raffinate from this extraction and, for comparative purposes, a portion of the unextracted P S -butylene polymer reaction product were neutralized with barium hydroxide. Table III shows the analysis of the resultant additives.

the foregoing table that extracting P S -butylene polymer reaction product in accordance with our invention results in an additive which has a viscosity of practically half of .that obtained when our process is not used. This of course permits much faster filtration and easier handling of the finished additive thus substantially reducing the processing costs. EXAMPLE 4 The oil-diluted hydrolyzed reaction product of P 8 and butylene polymer of Example 1 was contacted with 100 vol. percent of aqueous phenol (50 vol. percent water plus 50 vol. percent phenol) at 180 F. for about one hour.' The mixture was allowed to cool and settle at room temperature. The resultant system separated into three phases and the solvent was then removed from each phase. The bottom phase contained mostly low molecular weight organic acids which when neutralized with barium oxide were found to'be insoluble in oil. The middle phase was phosphoric acid of about 80% purity. The top raifinate phase, which represented over 90% of the charge, contained organic phosphorus acid and oil. This phase was neutralized with barium oxide and the product was found to be very bright and oil soluble and to have a low viscosity, i. e., it was very fluid and easily handled.

EXAMPLE 5 A butylene polymer having a molecular weight of about 700 was reacted with a mixture of 16% P 8 and 2% sulfur at a temperature of 400 F. for a period of hours. The reaction product was then hydrolyzed with steam at a temperature of 370 F. to 400 F. for a period of five hours until a constant acidity of 70 milligrams of NaOH per gram of product was obtained. The hydrolyzed product was diluted with an equal volume of an SAE 10 base oil and then heated and stirred at 200 F. for about one hour with 170 vol. percent of aqueous phenol (90 vol. percent water plus 10 vol. percent phenol). The mixture was allowed to settle at 175 F. and two phases formed. The bottom aqueous phenol solution was removed and stripped of water and phenol. The stripped bottoms fraction was approximately 70% phosphoric acid with the remainder being low molecular weight organic phosphorus acids. The top raflinate phase which represented 97% of the charge had an acidity of 25.7 milligrams NaOH per gram of rafiinate. The raffinate phase was neutralized with sufiicient barium hydroxide to neutralize the organic phosphorus acids. The resultant barium soap was very bright, oil soluble and had a low viscosity.

EXAMPLE 6 A plant run was also made to demonstrate our invention as follows: Butylene polymer having a molecular weight of about 1000 was reacted with P 8 at 450 6 F. for about 5 hours. This product was hydrolyzed with steam at 325 F. to 350 F. for 5 hours and diluted with 40 volume percent SAE 5 base oil; resulting in a mixture having a phosphorus content of 2.51%. The diluted mixture was then cooled to 150 F. and extracted with 25% by volume (based on volume of oil diluted reaction product) of a 33 volume percent isopropanol-water mixture. After mixing for one hour at 145-160 F. the batch was allowed to settle for six hours. The extract layer was drawn off and the oil phase was dried by heating to 270 F. The rafiinate had a phosphorus content of 2.32%. Suflicient barium hydroxide to give a barium to phosphorus charge weight ratio of 3.1 was then slurried with SAE 5 base'oil and added to the extracted P S -butylene polymer reaction product. This mixture was steamed for 5 hours at 270-310 F. and then filtered. It was very fluid and easy to filter and had a phosphorus content of 1.63 wt. percent and a barium to phosphorus ratio of 2.75. As pointed out hereinbefore, the process of our inven tion is applicable irrespective of the basic reagent employed to neutralize the compound. The foregoing examples have demonstrated the surprising results obtained when using a basic barium compound to neutralize the reaction product prepared in accordance with our invention. The following examples demonstrate the effectiveness of our process when using other basic compounds.

EXAMPLE 7 20 grams of the phenol extracted P S -butylene polymer reaction product of Example 5 was diluted with 10 cos. of naphtha and then neutralized with 0.8 gram KOH at 300 F. while blowing with nitrogen. The resultant potassium soap was very bright and had a low viscosity. For comparative purposes a portion of the unextracted hydrolyzed P S -butylene polymer reaction product of Example 5 was neutralized under essentially the same conditions with potassium hydroxide and the final product was cloudy and rather viscous.

EXAMPLE 8 The ethanol extracted P S -butylene polymer reaction product of Example 3 was neutralized with octadecyl amine. The resultant product was also very bright and had a low viscosity. 'This product was found to be very effective as an anti-rust agent.

As pointed out hereinbefore, one of the advantages of our invention is the preparation of a neutralized product having low trace metals content. To demonstrate this advantage, the metals contamination of the product of Example 6 was determined and found to have the following trace metals content in parts per million: aluminum, 47; iron, 74; calcium 13 and magnesium 41. By contrast to this, a product prepared in a manner similar to Example 6, but in accordance with the best prior art method in which a clay treating step was employed in place of an extraction step, contained the following trace metals content in parts per million: aluminum, 700; iron, 500; calcium, 55 and magnesium 1800.

The neutralized reaction products of a phosphorus sulfide and a hydrocarbon obtained in accordance with our invention are useful as additives in lubricant compositions used for the lubrication of internal combustion engines.

Percentages given herein and in the appended claims are weight percentages unless otherwise noted.

While we have described our invention by reference to specific embodiments thereof, the same are given by way of illustration only. Modifications and variations will be apparent from our description to those skilled in the art.

We claim:

1. In the preparation of an oil soluble lubricant additive wherein a normally liquid hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to about. 600 F. and the resultant reaction product hydrolyzed at a temperature of from about 220 F. to about 500 F. whereby inorganic acids of phosphorus and low molecular weight organic acids of phosphorus are formed, the improvement comprising contacting said hydrolyzed reaction product at a temperature in the range of from about 100 F. to about 212 F. for a period of time sufficient to remove said acids of phosphorus formed by said hydrolysis, with from about 10% to about 200% by volume of a mixture consisting of water and from about to about 95% by volume of a monohydroxy compound selected from the group consisting of phenol and alkyl alcohols having from 1 to about 5 carbon atoms, which monohydroxy compound has a solubilityv in water of at least about 5% by volume at the contacting temperature, and separating the hydrolyzed reaction product from said monohydroxy compound-water mixture.

2. In the preparation of an oil soluble lubricant additive wherein a normally liquid hydrocarbon is reacted with from about 1% to about 50% of a phosphorus sulfide at a temperature of from about 200 F. to about 600 F. and the resultant reaction product hydrolyzed at a temperature of from about 220 F. to about 500 F. whereby inorganic acids of phosphorus and low molecular weight organic acids of phosphorus are formed, and the hydrolyzed reaction product neutralized with a basic reagent, the improvement comprising contacting the unneutralized hydrolyzed reaction product at a temperature in the range of from about 100 F. to about 212 F. for a period of time sufficient to remove said acids of phosphorus formed by said hydrolysis, with from about to about 200% by volume of a mixture consisting of water and from about 5% to about 95% by volume of a monohydroxy compound selected from the group consisting of phenol and alkyl alcohols having from 1 to about 5 carbon atoms, which monohydroxy compound has a solubility in water of at least about 5% by volume at the contacting temperature, separating the hydrolyzed reaction product from said monohydroxy compound-water mixture, and neutralizing the extracted, hydrolyzed product with a basic reagent, whereby an oil soluble, neutralized reaction product of a normally liquid hydrocarbon and a phosphorus sulfide is obtained which is substantially free of salts of inorganic acids of phosphorus and low molecular weight organic acids of phosphorus.

3. The method of claim 2 in which the monohydroxy compound is phenol.

4. The method of claim 2 in which the monohydroxy compound is .ispropyl alcohol.

5. The method of .claim 2 in which the monohydroxy compound is isoamyl alcohol.

6. The method of claim 2 in which the basic reagent is a basic barium compound.

7. The method of claim '2 in which the normally liquid hydrocarbon is a butylene polymer having a molecular weight of from about 150 to about 50,000.

8. Themethod of claim 2 in which the phosphorus sulfide is phosphorus pentasulfide.

9. The method of preparing an oil soluble lubricant additive which comprises the steps of reacting a butylene polymer having a molecular weight in the range of from about 150 to about 50,000 with from about 1% to about of phosphorus pentasulfide'at a'temperature of from about 200 F. to about 600 F., hydrolyzing the P S butylene polymer reaction product at a temperature of from about 220 F. to about 500 F., contacting said hydrolyzed reaction product at a temperature in the range of from about 100 F. to about 212 F. with from about 10% to about 200% by volume of a mixture consisting of water and from about 5% to about by volume of isopropyl alcohol for a time sufiicient to remove the inorganic acids of phosphorus and low molecular weight organic acids of phosphorus formed by said hydrolysis, separating the extracted, hydrolyzed phosphorus pentasulfide-butylene polymer reaction product from said isopropyl alcohol-water mixture, and neutralizing the extracted hydrolyzed product with a basic barium compound.

References Cited in the file of this patent UNITED STATES PATENTS Bartleson Dec. 19, 1950 Lemmon et al. May 4, 1954 OTHER REFERENCES 

1. IN THE PREPARATION OF AN OIL SOLUBLE LUBRICANT ADDITIVE WHEREIN A NORMALLY LIQUID HYDROCARBON IS REACTED WITH FROM ABOUT 1% TO ABOUT 50% OF A PHOSPHORUS SULFIDE AT A TEMPERATURE OF FROM ABOUT 200*F. TO ABOUT 600*F. AND THE RESULTANT REACTION PRODUCT HYDROLYZED AT A TEMPERATURE OF FROM ABOUT 220*F. TO ABOUT 500*F. WHEREBY INORGANIC ACIDS OF PHOSPHORUS AND LOW MOLECUALR WEIGHT ORGANIC ACIDS OF PHOSPHORUS ARE FORMED, THE IMPROVEMENT COMPRISING CONTACTING SAID HYDROLYZED REACTION PRODUCT AT A TEMPERATURE IN THE RANGE OF FROM ABOUT 100*F. TO ABOUT 212*F. FOR A PERIOD OF TIME SUFFICIENT TO REMOVE SAID ACIDS OF PHOSPHORUS FORMED BY SAID HYDROLYSIS, WITH FROM ABOUT 10% TO ABOUT 200% BY VOLUME OF A MIXTURE CONSISTING OF WATER AND FROM ABOUT 5% TO ABOUT 95% BY VOLUME OF A MONOHYDROXY COMPOUND SELECTED FROM THE GROUP CONSISTING OF PHENOL AND ALKYL ALCOHOLS HAVING FROM 1 TO ABOUT 5 CARBON ATOMS, WHICH MONOHYDROXY COMPOUND HAS A SOLUBILITY IN WATER OF AT LEAST ABOUT 5% BY VOLUME AT THE CONTACTING TEMPERATURE, AND SEPARATING THE HYDROLYZED REACTION PRODUCT FROM SAID MONOHYDROXY COMPOUND-WATER MIXTURE. 